5. Transport properties 5. Transport properties 5.2 Electrical - PowerPoint PPT Presentation

5. Transport properties 5. Transport properties 5.2 Electrical conductivity 5. Transport properties 114 116 5.1. Semi-classical approximation Effective mass tensor Electron is a particle moving with group velocity: Wave-function changes according to: flat band ⇒ heavy electrons or holes dispersing band ⇒ light electrons or holes Bloch oszillation 5.2 Electrical conductivity 5.2 Boltzmann equation 5. Transport properties 5. Transport properties 115 117 electrons holes

5.2 Electrical conductivity 5. Transport properties 5.2 Electrical conductivity of metals 5. Transport properties 118 120 Temperature dependence (Matthiesen rule) At low temperatures: 5.2 Electrical conductivity of metals 5.3. Thermal conductivity 5. Transport properties 5. Transport properties 119 121 Wiedemann – Franz´sches Gesetz

5.4. Electrons in magnetic fields 5. Transport properties 5.4. de Haas – van Alphen effect 5. Transport properties 122 124 Oscillation of the magnetic susceptibility With external magnetic field electron hole open orbit 5.5. E ⊥ B – Hall Effect 5.4. Electrons in magnetic fields 5. Transport properties 5. Transport properties 123 125 condensation on Landau levels, B Landau – cylinders Non-closed orbits or carriers with different mobility or concentration ⇒ R H depends on magnetic field B